There are few studies that have studied the effect of incentives on the company and the company’s financial status on the behavior of corporate tax avoidance. The purpose of this study is to investigate the relationship between financial constraints and corporate tax avoidance. In this study, the financial constraint is defined as an independent variable and tax avoidance as a dependent variable. For this purpose, the financial data of 102 companies listed in the Tehran Stock Exchange are collected during the period 1388 to 1394. For measuring the financial constraint index, we use the index of Kaplan and Zingales (1997) which is customized for Iran by Tehrani and Hesarzadeh (1388). Also, the effective tax rate and the Book-tax differences are the indexes of the tax avoidance. The panel data regression is used to test the research hypotheses. The results indicate that there is no significant relationship between financial constraints and corporate tax avoidance.